/*
 * This file contains code from "C++ Primer, Fourth Edition", by Stanley B.
 * Lippman, Jose Lajoie, and Barbara E. Moo, and is covered under the
 * copyright and warranty notices given in that book:
 *
 * "Copyright (c) 2005 by Objectwrite, Inc., Jose Lajoie, and Barbara E. Moo."
 *
 *
 * "The authors and publisher have taken care in the preparation of this book,
 * but make no expressed or implied warranty of any kind and assume no
 * responsibility for errors or omissions. No liability is assumed for
 * incidental or consequential damages in connection with or arising out of the
 * use of the information or programs contained herein."
 *
 * Permission is granted for this code to be used for educational purposes in
 * association with the book, given proper citation if and when posted or
 * reproduced.Any commercial use of this code requires the explicit written
 * permission of the publisher, Addison-Wesley Professional, a division of
 * Pearson Education, Inc. Send your request for permission, stating clearly
 * what code you would like to use, and in what specific way, to the following
 * address:
 *
 *  Pearson Education, Inc.
 *  Rights and Contracts Department
 *  75 Arlington Street, Suite 300
 *  Boston, MA 02216
 *  Fax: (617) 848-7047
*/

#include "tmpl_preamble.h"
#include "Sales_item.h"

// implement strcmp-like generic compare function
// returns 0 if the values are equal, 1 if v1 is larger, -1 if v1 is smaller
template <typename T>
int compare(const T& v1, const T& v2)
{
	if (v1 < v2) return -1;
	if (v2 < v1) return 1;
	return 0;
}

// repeats body of compare but with comments
int f(int v1, int v2)
{
	if (v1 < v2) return -1;  // < on two objects of type T
	if (v2 < v1) return 1;   // < on two objects of type T
	return 0;                // return int;  not dependent on T
}

// special version of compare to handle C-style character strings
template <>
int compare<const char*>(const char* const& v1,
						 const char* const& v2)
{
	return strcmp(v1, v2);
}

// returns 0 if the values are equal, -1 if v1 is smaller, 1 if v2 is smaller
int compare(const string& v1, const string& v2)
{
	if (v1 < v2) return -1;
	if (v2 < v1) return 1;
	return 0;
}

int compare(const double& v1, const double& v2)
{
	if (v1 < v2) return -1;
	if (v2 < v1) return 1;
	return 0;
}

int main()
{
	// T is int;
	// compiler instantiates int compare(const int&, const int&)
	cout << compare(1, 0) << endl;

	// T is string;
	// compiler instantiates int compare(const string&, const string&)
	string s1 = "hi", s2 = "world";
	cout << compare(s1, s2) << endl;
	{
		short s1, s2;
		int i1, i2;
		compare(i1, i2);    // ok: instantiate compare(int, int)
		compare(s1, s2);    // ok: instantiate compare(short, short)
	}
	char* cp1 = "world", *cp2 = "hi";
	cout << compare(cp1, cp2) << endl;       // compares pointer values!

	{
		const char* cp1 = "world", *cp2 = "hi";
		int i1, i2;
		compare(cp1, cp2); // calls the specialization
		compare(i1, i2);   // calls the generic version instantiated with int
	}
	{
		const char* cp1 = "world", *cp2 = "hi";
		compare<string>(cp1, cp2);  // converts arguments to string
	}
	return 0;
}

